Tanks don't vary that much in location of weakspots. They vary a little but not that much.
And weakspots are not going to cause a dramatic difference if your gun is too weak.
They help but only to a certain degree.

If you can circle the tank (Best to worst):
1. Rear armor (Lowest armor value and some tanks keep ammo there)
2. Side armor (Try hitting the rearmost part of the side armor usually as some tanks have ammo there)
I tried shooting the tracks but it doesn't cause as much damage as shooting the armor.
Unless you want to detrack the tank, in which case shoot the first or last wheel.

If you can only shoot the front of the tank (Best to worst):
1. Front viewport (the horizontal slit commander looks out of, not all tanks have it)
This is small and hard to hit, but it gives good penetration and a possible crew hit.
2. Front lower hull (called the glacis plate, its good because its usually flat and thin armor)
On some like the Jagdtiger, it really penetrates well. On others, its not great but still better than the alternative of shooting the upper hull.
3. Any flat hull surface you can find (It is better than shooting a sloped surface)
4. In between turret and hull (when you can't hit any other weakspot)
Upper hull is terrible to shoot as it is sloped and armored thickly.
Shooting tracks from the front causes little to no damage, so bad target unless you want to detrack the tank.
The gun socket armor (called the mantlet) and the gun are usually heavily armored and inpenetratable.
I tried shooting machine gun ports but that doesn't work well.

If all you can hit is the turret (Best to worst):
1. Rear of turret
2. Side of turret
3. In between turret and hull (Not great, but still better than shooting the front of the turret)
Shooting the front of the turret for most tanks is the absolute worst place to shoot.
Usually if all you can hit is the turret, unless the tank is below your tier, don't bother fighting, escape and get into a better position.

Tank specific differences:
Not that many.
KV5 has a big bubble hatch in front you should shoot. It is extremely easy to penetrate.